Many processes are known in the art for the carbonylation of acetylenically and olefinically unsaturated compounds. A review of such processes is provided by J. Falbe, "New Synthesis with Carbon Monoxide", Springer-Verlag, Berlin Heidelberg New York, 1980. Typically, the processes involve the reaction of an olefinically unsaturated compound with carbon monoxide and, in some cases, hydrogen or a nucleophilic compound having a removable hydrogen atom, in the presence of a carbonylation catalyst system. In many instances, the carbonylation catalyst system comprises a Group VIII metal compound and a ligand such as phosphine.
One type of catalyst system which has been disclosed in recent years comprises a source of a Group VIII metal and a pyridyl phosphine.
Kurti Kurtev et al, Journal of the Chemical Society, Dalton Transactions, 1980, pages 55 to 58 disclose catalyst systems comprising a rhodium or ruthenium compound and a pyridyl monophosphine, and their use in the carbonylation of hex-1-ene.
European Patent Application Number EP-A1-0271144 discloses the use of catalyst systems comprising a palladium compound, a pyridyl monophosphine and an acid in the carbonylation of acetylenes with hydroxyl-containing compounds. Unlike EP-A1-0259914, the broadest definition of phosphines said to be suitable for use in the carbonylation process is restricted to phosphines in which all three phosphorus substituents are aromatic.
European Patent Application Number EP-A1-0282142 discloses the use of catalyst systems comprising a palladium compound, a pyridyl monophosphine and an acid in the carbonylation of olefins with hydroxyl-containing compounds. Unlike EP-A1-0259914, the broadest definition of phosphines said to be suitable for use in the carbonylation process is restricted to phosphines in which all three phosphorus substituents are aromatic.
European Patent Application Number EP-A2-0305012 discloses catalyst systems comprising a palladium compound, a pyridyl diphosphine, an acid and a quinone, and their use in the carbonylation of olefins to afford polymers.
None of the aforementioned references discloses pyridyl monophosphines in which the phosphorus atom has a simple, aliphatic substituent, nor do they suggest that such phosphines may be attractive as components for a carbonylation catalyst. Indeed, for carbonylation catalysts other than those suitable for preparing polymers; that is, carbonylation catalysts comprising a quinone; the aforementioned references clearly teach away from such phosphines.
Chem. Ber., 115 (9), 3085-95 (1982) discloses methyl-di-2-pyridylphosphine and dimethyl-2-pyridylphosphine.
J. Mol. Spectrosc., 34 (2), 245-56 (1970) discloses n-butyl-di-2-pyridylphosphine.
It has now been found that pyridylmonophosphines in which the phosphorus atom has a simple, aliphatic substituent, are highly effective as carbonylation catalyst components, especially in the carbonylation of acetylenes.